This section provides background information related to the present disclosure, which is not necessarily prior art.
Exhaust treatment systems treat engine exhaust before the exhaust is released into the atmosphere, such as by filtering undesirable particles from the exhaust. For example, exhaust treatment systems often include a particulate filter that filters soot and other particulates from the exhaust. To determine whether the particulate filter is operating properly, a particulate matter sensor is arranged downstream of the particulate filter to measure the particulate content of the exhaust.
Some particulate matter sensors include a resistance sensor, which changes resistance in response to a buildup of particulates thereon that should have been filtered by the particulate filter. If the sensor measures an unacceptable level of particulates in the exhaust, it is likely that the particulate filter is not operating properly. For example, the particulate filter may be cracked, thereby reducing its effectiveness. While current particulate matter sensors are suitable for their intended use, they are subject to improvement. For example, the resistance sensor may fail or become inaccurate, thereby making it difficult to determine whether the particulate filter is operating properly. The present teachings provide for an improved particulate matter sensor that addresses this issue, as well as numerous others.